This claims priority under 35 U.S.C. .sctn.119(e) to U.S. Provisional Application Ser. No. 60/076,252, filed Feb. 27, 1998, which is expressly incorporated by reference herein.
The present invention relates to an apparatus for bending tubes, and particularly to a mandrel assembly for an apparatus for bending tubes. More particularly, the present invention relates to a mandrel assembly that is positioned to lie in a tube being bent during the bending process.
Tube benders are used to form bends in tubes at predetermined bend locations. Tube benders include a round bend die around which a tube is bent at the predetermined bend locations. During bending, the tube has a tendency to "flatten out" so that the bent portions of the tube no longer have a cylindrical shape.
To prevent the tube from flattening out, a mandrel ball is positioned within the tube at the predetermined bend location where the tube is to be bent. The mandrel ball is coupled to a mandrel rod that positions the mandrel ball at the predetermined bend location. During bending, the mandrel ball supports the predetermined bend location of the tube being bent to maintain the tube's cylindrical shape. The tube is then advanced so that the next predetermined bend location is positioned adjacent the round bend die with the mandrel ball positioned at the new predetermined bend location.
According to the present invention, a mandrel assembly for a tube bender is provided including a mandrel rod, a mandrel ball, and a coupler configured to couple the mandrel ball to the mandrel rod. The mandrel rod is adapted to be coupled to the tube bender. The mandrel ball has a body and a projection coupled to the body. The coupler includes a link, a first connector member, a second connector member, and a retainer. The link includes body and a collar. The body includes a first end coupled to the mandrel rod and a second end spaced apart from the first end. The collar is coupled to the second end of the body. The first and second connector members are positioned to lie over the second end of the body and cooperate to define a groove sized to receive the collar of the link and a socket sized to retain the projection of the mandrel ball. The retainer is positioned to lie over the first and second connector members and the link to secure the first and second connector members to the link.
In a preferred embodiments, the retainer is moveable relative to the link. The retainer engages the first and second connector members to restrain movement of the connector members relative to the link. The mandrel rod includes a lubricant passage; the link includes a lubricant channel in communication with the lubricant passage of the mandrel rod; and the retainer includes a lubricant channel configured to communicate with the lubricant channel of the link. The link includes an outer surface having a diameter less than a diameter of an inner surface of a tube gripper that grips an inner surface of the tube being bent.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.